Many types of wellbore measurement instruments are known in the art. Such instruments generally include an elongated, pressure resistant housing configured to move through a wellbore drilled through subsurface rock formations. The housing generally includes one or more sensors that measure selected parameters in the wellbore. The parameters, without limitation, include those related to the physical properties of the wellbore itself (e.g., temperature, pressure, fluid content, wellbore geodetic trajectory); construction of the wellbore (e.g., torque and/or axial force applied to a drill bit) and the formations surrounding the wellbore (e.g., resistivity, acoustic velocity, neutron interactive properties, density, and pore fluid pressure and composition).
The housing may be configured to be moved through the wellbore using several different techniques known in the art, including, without limitation, within a drill string or other jointed pipe string, on coiled tubing, or on armored electrical cable or slickline.
Irrespective of the conveyance device used, and irrespective of the types of sensor(s) used in any particular wellbore measurement instrument, such instruments typically include some form of data storage device therein and/or a controller that may be reprogrammed so that measurement and/or data storage and communication functions of the instrument may be changed to suit a particular purpose. Access to the data storage and/or access to the instrument controller typically requires electrical connection to a suitable communications port in the instrument, particularly for those instruments designed to be conveyed other than on an armored electrical cable. Communication ports known in the art include electrical connectors that are designed specifically for the particular instrument. More specifically, the arrangement of electrical contacts in the particular connector is typically unique to the type of instrument. Such arrangement of electrical contacts also requires that an electrical cable used to connect the communication port to a surface device (such as a computer or other data processor) must also be specially made to engage the electrical contacts on the communication port connector. Such specialized communication port connectors and corresponding cables can be expensive to manufacture, and may create logistical difficulties in the event of cable failure, e.g., timely obtaining a replacement.
Additionally, the necessity of a cable reduces the ease and speed with which the communication can take place. Finally the communication is impossible without a PC or similar surface device, adding complexity and more cost to the process. A sonic device (buzzer) is another instrument known in the art used to relay information between the measuring instrument and the instrument's human operator. The method used with the buzzer is to communicate with the tool operator through a series of high volume “beeps” of selected timing and duration. This technique is limited due to the difficulty in hearing on an average rig floor which has a number of very high volume sound sources. Not only does external noise interfere, but sound penetration through the typical housing of downhole tools is limited. Lastly, the range of information that can be transferred is minimal when dealing with sound communication in an uncontrolled environment.
What is needed is a more reliable device for communicating certain instrument signals to the instrument operator and/or to a surface device.